It may be that for you to pay on the day you may need to collect on a week day, as the back room finance people who can access the bank account may not be working weekends. It is not unreasonable for the dealership to be sure funds have been transferred, it is also not unreasonable for you to be absolutely happy with the car before paying any of your money.
There’s mid ground in there somewhere, you may need to chat with the dealership in order to find it.
I'm Autistic, if I say something you find offensive, please let me know, I can guarantee it was unintentional.
I'll try to give my honest opinion but am always open to learning.
Mark